U.S. President Barack Obama "held and hugged" grieving family members in Orlando, Florida, Thursday but said he had no easy answers to their questions of why mass shootings continue to happen.

Obama and Vice President Joe Biden met privately with relatives of the 49 people killed and the 53 wounded at Pulse, a gay nightclub, last Sunday in the largest mass shooting in U.S. history.

He said the families' grief is "beyond description."

'Hearts are broken'

Obama called for solidarity in the face of the attack, saying those killed in the attack "could be our families," and telling those directly affected by the shootings that "our hearts are broken, too."

"If we don't act, we will keep seeing more massacres like this because we will be choosing to allow them to happen," he said.

President Barack Obama, left, and Vice President Joe Biden place flowers at a makeshift memorial for shooting victims of the massacre at a gay nightclub in Orlando, Fla., June 16, 2016.

Airborne on the flight from Washington to the southeastern U.S. city, White House spokesman Josh Earnest said that Obama "feels there is no more tangible way to show support for Orlando than to go there."

Earnest said the president "wants to show [that] Americans stand shoulder to shoulder with the people of Orlando."

The attack occurred in the early hours of Sunday when an American-born Muslim sprayed round after round of bullets at revelers who were dancing to Latin music and partying with friends.

The three-hour siege ended when police knocked holes into the Pulse nightclub and killed the gunman, Omar Saddiqui Mateen, in a shootout.

Obama and Biden also met with the first-responders, medical staff and law enforcement officials to thank them for their efforts, and the owners and staff of the nightclub where the attack occurred. They also laid wreaths at a vigil site.

Florida legislators Senator Marco Rubio and Representative Corrine Brown flew with Obama to Orlando aboard Air Force One, but they did not take part in his meetings with those affected by the shooting.

“I can’t speak for [the president] or what he is going to do – but I hope it does bring some comfort to the victims that he is coming and to show that he does care," said Al New, standing in the front of the makeshift memorial that has become a gathering point for Orlando residents in the wake of the shooting attack.

The plaza in front of the Dr. Phillips Center for the Performing Arts is full of flowers and other memorabilia for the victims of the attack.

Several vigils have been held here since the attack, and a steady stream of people pass by to pay their respects.

Josh Korshak stopped by Thursday morning in advance of Obama's visit.

"I mean a lot of people say Obama isn’t – you know – he hasn't gone through it just as much as we have, and he’s been acting almost indifferent to it as well," he said. "But, I think he’s definitely going to try and talk to these people and tell them, 'Hey I’m here for you.' What can you do, you know?"

A member of the Billy Graham Evangelistic Association leads an impromptu prayer with two locals at Orlando's victim memorial, June 16, 2016. (Photo: A. Arabasadi/VOA)

Candice King-Palgut described herself as not a fan of Obama's politics, but had great respect for his humanity.

"He feels deeply, and I appreciate that," she said.

She summed up with her own post-shooting prescription: "No amount of trying to keep people out, that’s not going to fix anything. We just have to love each other and be more mindful of each other. Be kinder, be gentler, be truer."

Meanwhile, the Senate Homeland Security committee is asking Facebook to provide whatever data it has on any account linked to the 29-year-old Mateen.

In a letter Wednesday, committee chairman Ron Johnson said his staff obtained information that Mateen made several Facebook posts Sunday, including pledging allegiance to Islamic State leader Abu Bakr al-Baghdadi and telling the U.S. and Russia to stop bombing the militants.

Mateen also said there would be more attacks in the U.S. in the coming days.

FBI probe

Other lawmakers want to know more about the FBI's earlier contacts with Mateen, whom investigators interviewed in 2013 and 2014 after he bragged to coworkers about ties to al-Qaida.

Agents could not verify the allegations and closed their probe.

"We know that the FBI had looked closely at him because of concerns from coworkers and others," Michigan Senator Debbie Stabenow told VOA. "I’d like to know more about their decisions. He was on a terror watch list and removed."

Illinois Senator Richard Durbin said, “Not once but twice [the FBI was] warned that [Mateen] was a dangerous man. Their investigation concluded there was nothing more they could do. We wish there had been a different outcome – many people would be alive today."